In recent years, MIMO (Multi-Input Multi-Output) technology has been studied for application to mobile communication systems which are radio communication systems, as means of greatly improving communication throughput. Among such MIMO technologies, PARC (Per Antenna Rate Control) technology (“3GPP TR25.876”) is attractive, which measures propagation quality between transmission and reception antennas, and adaptive modulation is performed according to each propagation quality of the transmission and reception antennas to optimally allocate transmitting resource.
PARC technology handles transmission rates independently for each of multiple antennas, and with respect to retransmission as well, a Cyclic Redundancy Check (CRC) can be added at each transmission antenna and retransmission controlled independently to promote improvement of communication efficiency.
In Japanese Laid-open Patent Publication No. 2004-112098, an invention is proposed relating to retransmission of MIMO technology which enables different transmission weighting from the initial transmission and obtaining of diversity gain.